Kayo, how does that Xtra X-1 sound? And is the volume too twitchy with those ER6i's? One of the main reasons I got the Tomahawk was concern about finer control of volume than an amp that could drive monster phones would allow, and I read that the X-1 could power the HD600 easily. Since the ER6i are half the impedance of my IEMs, I'd be afraid of deafening myself with a slight nudge of the pot. Nice setup, though!

Packgrog, I've only had the Xtra for 2 days now, totalling at about 10 hours listening time. I seems to me that its sound is not very neutral. It's what I, and others, would describe as having a 'musical' signature. Depending on how you like your amps, this can be good or bd. The bass is little boomy at the moment, and the highs a tad shrill for my liking, but I expect this to tame over time.

With the ER6is tweaking the volume is not as sensitive as I thought it would be. Obviously switching between my HD595s and ER6i, I have to lower the volume by about half.